1. Field of the Invention:
The present invention relates to the field of spring energized gyros.
2. Prior Art:
Spring energized gyros are two axis free gyros having a rotor which, when the unit is fired, is spun up by a prewound spring. In a simplest form, a drive member is coaxial with and extends to engage the end of the rotor shaft. Upon firing of the device by squib or otherwise, a prewound spring spins the drive member, with the drive member, rotor shaft and either the drive spring or another spring then cooperating to disengage and withdraw the drive member. Once withdrawn the rotor in an instrument in use will coast at a relatively high speed throughout the relatively short duration of its use, or if in test, will coast to a stop after a few minutes. In general during testing, the rotor will not stop in a position aligned with the drive member, so that in order to re-engage the drive member with the rotor shaft and rewind the spring, access to the instrument interior is required to allow manual repositioning the gimbals of the gyro for re-engagement of the drive member. Since the purpose of testing normally is to verify that the instrument as closed and sealed has the full required freedom and accuracy of operation, the opening of the instrument to rearm the same negates a substantial purpose of the test, as it provides an opportunity for the entry of foreign matter, may result in repositioning or breaking of lead wires, etc., which can only be discovered by again retesting. Accordingly, it is the purpose of the present invention to provide for the caging and rearming of a spring wound gyro after testing without having to gain entry into the main instrument enclosure, thereby eliminating the opportunity for entry of foreign matter, etc., and making testing thereof prior to actual use much more meaningful and a much more valid verification of what the performance in use will be.